In IPTV (Internet protocol television) or other video transmission applications, video signals are processed at different stages. A video signal is usually compressed into a bitstream, which may also be referred to as an elementary stream (ES). The bitstream or ES may be then packetized into a transport stream (TS) and transmitted through an IP channel. The bitstream received at a decoder can be decoded. Error concealment may be performed to the decoded video if necessary. Video quality at the decoder is generally lower than that of the original video due to compression loss and transmission errors. To examine objectively how much the video quality is degraded, the video quality can be measured using transport stream, elementary stream or decoded video.